A-D-Galactosidation

Abbreviations All, allyl MP, dimelhylaminopyridine or 2,4,6-trimelhylpyridine MOM, methoxy-methyl Piv, pivaloyl Tr, trityl other abbreviations are the same. Obtained accompanied with the 3,4-0-( methyl orthoacetyl)-a-D-galactoside the 0-deacetyl derivative was also reported. Inserted as a reference reaction. A mixture of two diastereoisomers. On hydrolysis (R = F), 3,6-dideoxy-3,6-difluoro-D-glu-copyranose is formed. Methanolysis gives methyl 3-deoxy-3-fluoro-a-D-galactopyranoside. 

This enzyme [EC 3.2.1.22] catalyzes the hydrolysis of melibiose to yield galactose and glucose. It will also act on terminal, nonreducing a-D-galactose residues in a-D-galactosides. In addition, it will hydrolyze a-D-fucosides. 

Methyl 6-deoxy-6-fluoro-a-D-galactoside (10 0.5 g, 2.6 mmol) and pyrophoric Raney Ni (1 g) in MeOH (50 mL) were treated with H2 at 100 "C/ 120 atm for 9 h. The filtered solution was evaporated and the residue extracted with CHC13 (3 x 50 mL). After removal of the solvent the reduced product was hydrolyzed with 2.5 M H2SG4 (5 mL) at 100 C for 2 h. The resulting crude 11 was converted into the corresponding benzylphenylhydrazone mp 177—178 C. 

V/3, 170 (0-S02-R - F) 6-Deoxy-a-D-galactoside Methyl 6-Fluoro- E10b2, 327 f. (Educt)... 

Deoxyribonucleate 5 -oligonucleotidohydrolase a-D-Galactoside galactohydrolase /(-D-Galactoside galactohydrolase a-D-Mannoside mannohydrolase 1 — 4- -D-Xylan xylohydrolase Pyrophosphate hydrolase... 

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